i am using linux as firewall and transparent proxy, yesterday when i browsed a site. http://www.whatismyipaddress.com

i surprised to see my private ip address. it also told me;

1. public ip address
2. private ip address
3. linux version + squid version
4. linux hostname


is this possible to hide 2,3,4 from this site using iptables?

What you need is not iptables but to route your traffic through an anonymous proxy: TOR, JAP or find lists of proxies with your favourite searchengine. (Nota bene: this is not a Linux Security question).

iptables won't work for this because the info in question is in the HTTP headers being sent to the server from your box... the most common approach i know of to deal with these "information disclosure" issues is to use a proxy server to filter (or edit) your HTTP headers... privoxy is specially-made for situations like this, but even a generic proxy like squid can be configured to control HTTP headers (look into the header_access options)... for example:the above in squid would prevent the User-Agent HTTP header from being sent to anywhere in the example.com domain... you can, of course, make it stop for all connections also, with something like:usually it takes a little bit of time for you to find the best amount of header filtering for you... oh, and here's an example of how to edit a header:when this is used with the previous .example.com example, the header will be replaced instead of just filtered...

sometimes you'll HAVE to edit a header instead of filtering it because a server you want to use won't let you work without the header... well, at least that's been my experience... =)

NOTE: my suggestion only addresses points #2, #3, and #4 - to address point #1 you'd need to add software such as Tor (as mentioned by unSpawn) into the mix...